Investigation of the role of Gd3+ in energy transfer mechanism of Eu3+ activated LaNbO4 phosphors for solid-state lighting
In the field of illumination and energy, phosphor-converted white light-emitting diodes (pc-WLEDs) have emerged as critical lighting sources due to their longevity, high efficiency, exceptional brightness, reliability, and eco-friendliness. Phosphors in pc-WLEDs are based on different combinations o...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | Materials Research Express |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/2053-1591/adee82 |
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| Summary: | In the field of illumination and energy, phosphor-converted white light-emitting diodes (pc-WLEDs) have emerged as critical lighting sources due to their longevity, high efficiency, exceptional brightness, reliability, and eco-friendliness. Phosphors in pc-WLEDs are based on different combinations of host and dopant ions. Designing a single matrix with dual-emitting centers and color-tunable properties has become a trend in the development of phosphors for such applications. Lanthanum niobate (LaNbO _4 ), due to its remarkable chemical and thermal stability, is an excellent host material and europium (Eu ^3+ ) ion is a key red activator in several inorganic phosphor materials. Herein we studied the role of Gd ^3+ in the energy transfer mechanism in Eu ^3+ -doped LaNbO _4 . Using a solid-state reaction route, we initially synthesized La _(1− _x _) NbO _4 : x Gd ^3+ by varying concentrations of Gd ^3+ . The optimal concentration of Gd ^3+ was determined from the emission studies. Subsequently, fixing that optimal Gd ^3+ concentration, we prepared Gd ^3+ and Eu ^3+ co-doped La _(1 _-x-y _) NbO _4 : x Gd ^3+ / y Eu ^3+ by varying the Eu ^3+ content. XRD analysis was performed to identify the structure and phase purity of all synthesized phosphors. The vibrational and absorption characteristics were examined through FTIR and reflectance spectroscopy, respectively. Gd ^3+ doped LaNbO _4 displayed a sharp emission at 313 nm due to Gd ^3+ transitions and a broad blue emission around 410 nm from the host. Along with the aforementioned emissions, Gd ^3+ /Eu ^3+ codoped phosphors exhibited orangish-red emission with a maximum emission at 614 nm with ^5 D _0 to ^7 F _2 transition of Eu ^3+ ion. Upon excitation at 273 nm, we observed energy transfer from the host and Gd ^3+ to Eu ^3+ , leading to an enhancement in red emission. Additionally, we performed morphology and elemental analyses using SEM and EDAX, confirming that no impurities other than the initial precursors were present. CIE chromaticity coordinates of LaNbO _4 :Gd ^3+ /Eu ^3+ phosphors correspond to the orangish-red region, making them promising red-emitting materials for lighting and displays. |
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| ISSN: | 2053-1591 |